It's no surprise that Glee's ratings aren't what they used to be. And with big changes coming to the FOX musical next season, I'm sure Ryan Murphy & Co. are trying to do everything they can to juice up the numbers in season 4. And that includes the continuation of big stunt casting.

Today, FOX is holding their upfronts, an annual event held throughout the week where the networks unveil their fall schedules to advertisers. And aside from the fact that Glee will be moving to Thursdays at 9pm for season 4 (behind The X Factor in the fall and American Idol in the spring), FOX President Kevin Reilly announced during a conference call this morning that Sarah Jessica Parker and Kate Hudson have been cast in multi-episode arcs come the fall.

Hudson is currently scheduled for six episodes. It is unclear at this point how many episodes the Sex and the City star will be in. (According to the press release, "Additional details about her character and storyline will be released at a later date."). Chris Colfer appeared on Live! With Kelly this morning and revealed that Parker will play a mentor to him, so it looks like she could become a series regular if it works out.

In the conference call, Reilly also teased what the format of season 4 will be like, the "revolutionary" idea, as Ryan Murphy put it months ago. Deadline is reporting that "it will feature a 'show within a show,' following some of the McKinley High graduates as they attend the New York performing arts school while also 'adding some new faces' back in Ohio."

This confirms what's been teased in the past several weeks, that we would in fact actually see the New York bound high school graduates as they venture forward. And we also now know that season 4 will switch back and forth between New York and Ohio. I'm sure some fans will wonder if it could be too much to fit into each episode.

What do you make of all this season 4 news? Are you looking forward to Sarah Jessica Parker and Kate Hudson? And does the "show within a show" format sound intriguing?